PubMed Health⌕ Search

Biomedical subjects

P Weir

Publications and source records attributed to P Weir.

At least 19 recordsLinked to original sources
PubMed2001

Impaired fatty acid oxidation in propofol infusion syndrome.

Propofol infusion syndrome is a rare but frequently fatal complication in critically ill children given long-term propofol infusions. We describe a child who developed all the clinical features of propofol infusion syndrome and was treated successfully with haemofiltration. Biochemical analysis before haemofiltration showed a large rise in plasma concentrations of malonylcarnitine (3.3 micromol/L) and C5-acylcarnitine (8.4 micromol/L), which returned to normal after recovery. Abnormalities are consistent with specific disruption of fatty-acid oxidation caused by impaired entry of long-chain acylcarnitine esters into the mitochondria and failure of the mitochondrial respiratory chain at complex 11.

Acidosis↗
PubMed2000

Intravenous clonidine infusion in critically ill children: dose-dependent sedative effects and cardiovascular stability.

Clonidine is used for analgesia and sedation in paediatric anaesthesia, but there are no data on its sedative properties and side effects in critically ill children. We studied 30 ventilated children aged 10 yr and under to determine an effective i.v. dosing range and to assess its cardiovascular effects. Twenty non-paralysed, ventilated children were given a background infusion of midazolam 50 micrograms kg-1 h-1 combined with a variable clonidine infusion (0.1-2 micrograms kg-1 h-1) to maintain optimal sedation. The effects of clonidine 1 microgram kg-1 h-1 on cardiac index were measured in 10 postoperative cardiac patients using a reverse Fick method. Dose-dependent sedation was achievable (713 out of 861 h) without cardiovascular side effects, but an infusion limit of clonidine 1 microgram kg-1 h-1 was inadequate in two patients. An increased dose limit of 2 micrograms kg-1 h-1 combined with midazolam 50 micrograms kg-1 h-1 achieved satisfactory sedation scores for 602 out of a total of 672 h studied with no failures. Clonidine in combination with midazolam at 1 microgram kg-1 h-1 was not associated with significant changes in heart rate arterial pressure or cardiac index.

Adrenergic alpha-Agonists↗
PubMed2000

The efficacy and safety of epidural infusions of levobupivacaine with and without clonidine for postoperative pain relief in patients undergoing total hip replacement.

UNLABELLED: We assessed the efficacy and tolerability of epidural infusions of levobupivacaine, levobupivacaine plus clonidine, and clonidine for postoperative analgesia in 86 patients undergoing total hip replacement. For each group, an epidural cannula was inserted before surgery and 15 mL of 0.75% plain levobupivacaine was administered. Three hours later, an epidural infusion (6 mL/h) of levobupivacaine 0.125% (L), levobupivacaine 0.125% plus clonidine 8.3 microg/mL (LC) or clonidine alone (8.3 microg/mL) (C) was initiated. Morphine consumption was recorded for the following 24 h as were visual analog pain scores and the degree of sensory and motor blockade. The mean (median) morphine consumption was lowest in the combination group (LC),14 (7) mg; higher in the clonidine group (C), 23 (21) mg; and highest in the levobupivacaine group (L), 37 (36) mg (P = 0.022). The median times until the first request for analgesia which were 2. 9, 5.9, and 12.5 h for Groups L, C, and LC, respectively (P < or = 0. 01). There were no statistical differences among the groups regarding the maximum degree of postoperative motor blockade. On average, the systolic blood pressure in the two clonidine groups was slightly lower than in those from the levobupivacaine group. We conclude that the epidural administration of a combination of levobupivacaine plus clonidine is well tolerated and gives better analgesia than either drug used alone. IMPLICATIONS: In patients undergoing total hip replacement, the addition of the alpha(2)-adrenergic agonist clonidine to epidural infusions of levobupivacaine significantly improved postoperative analgesia.

Aged↗
PubMed1999

The reach-to-grasp movement: A new look at an old problem?

This commentary raises some issues still unresolved in the study of the reach-to-grasp movement, namely the operational definition of the components of the reach-to-grasp movement, the independence of these components, and the equivocal interpretation of the existing literature. Lastly, this commentary addresses issues pertaining to object properties that require both visual and haptic determination.

Biomechanical Phenomena↗
PubMed1998

The epidemiology of deliberate self poisoning presenting to Christchurch Hospital Emergency Department.

AIM: To review the recent epidemiology of deliberate self poisoning presentations to Christchurch Emergency Department and to compare this with 1992 and 1989 data. METHOD: A retrospective analysis of case and computer records over the twelve month period of 1996 was conducted and compared with published data for 1992 and 1989. RESULTS: There were 713 presentations in 1996 to Christchurch Emergency Department with deliberate self poisoning, representing 1.1% (compared with 1.2% 1992; 0.96% 1989) of total presentations. The female to male ratio was 1.9:1.0 (compared with 1.5:1.0, 2.1:1.0). 70.1% of patients presenting were under the age of 35. The principal drugs ingested were antidepressants 20% (compared with 24.4%; 15.7%) paracetamol (16.7% compared with 16.9%; 10.6%) hypnotics/anxiolytics 15.6% (benzodiazepines 11.0% compared with 23.6%; 18.0%), antipsychotics 10.7% (compared with 16.1%; not reported). Gastric decontamination was given to 61% (compared with 73% 1992), charcoal alone used in 54% (compared with 46%; 0.4%), gastric lavage and charcoal 7% (compared with 27%; 78%). 39% received no gastrointestinal decontamination (compared with 27% 1992). Of the patients presenting, 68.9% were admitted (compared with 59%; 66%), 10.2% to Intensive Care Unit (compared with 11%; 18%). There were 6 deaths (compared with 2; 2). CONCLUSION: Deliberate self poisoning remains a problem mainly of the young with a gender ratio favouring female. Antidepressant medications, paracetamol, benzodiazepines and antipsychotics remain the most common classes of drugs taken alone or in combination. An important trend within the antidepressants is the increasing misuse of selective serotonin reuptake inhibitors. Rates of admission to hospital and the Intensive Care Unit have changed but mortality rates have had no significant change over the three time periods. Gastrointestinal decontamination techniques employed follow a trend towards the use of activated charcoal and away from gastric lavage.

Acetaminophen↗
PubMed1998

The outcome of children requiring admission to an intensive care unit following bone marrow transplantation.

We report the results of a retrospective study of the role of intensive care unit (ICU) admission in the management of 367 children who underwent bone marrow transplantation (BMT) at a tertiary referral institution. 39 patients (11%) required 44 ICU admissions for a median of 6 d. 70% received marrow from unrelated donors, half of which were mismatched; 80% had leukaemia and two-thirds were considered high-risk transplants. Respiratory failure was the major reason for admission to ICU. 75% of admissions required mechanical ventilation (for a median of 5 d) and 20 patients had lung injury as defined by the criteria of the Seattle group. None of 11 patients with proven viral pneumonitis survived (P = 0.06) and only one of 20 patients with lung injury survived (P < 0.01). Six of seven patients with a primary neurological problem survived (P < 0.001); these appear to represent a good outcome group. Age, the presence of graft-versus-host disease, the use of inotropes, isolated renal or hepatic impairment, and paediatric risk of mortality (PRISM) score were not predictive of outcome. In total, 12 patients (27% of admissions) survived and were discharged from hospital 30d or more after admission and eight (18%) survived >6 months. ICU admission can be beneficial to selected children post-BMT but it may be less useful in proven viral pneumonitis. Where mechanical ventilation is required, the duration of this support should be limited unless there is rapid improvement.

Acute Disease↗
PubMed1997

Carbon dioxide embolism during laser endometrial ablation.

A patient undergoing endometrial ablation with an Nd-YAG laser, a carbon-dioxide-cooled coaxial fibre and an exposed fibre tip suffered a carbon dioxide embolism resulting in cardiac arrest. A full recovery was made with no neurological deficit.

Carbon Dioxide↗
PubMed1997

Penetrating eye injuries in rural New South Wales.

PURPOSE: To determine the epidemiology and outcomes of penetrating eye injuries in a rural Australian setting. METHODS: A retrospective study of an 11 year period to identify 77 cases of penetrating eye injury in Lismore, New South Wales. RESULTS: The commonest cause of penetrating eye injury was fencing wire followed by hammering metal. The average age was 32.6 years, and males were involved in 88% of cases. A final visual acuity of 6/12 or better was achieved in 61% of cases. Enucleation was performed in 14%. Visual outcome was best for wounds involving the cornea only. CONCLUSIONS: Penetrating eye injuries are potentially devastating to vision, but with modern surgical techniques patients are likely to achieve reasonable vision. Prevention requires education to ensure adequate protective measures are taken in potentially hazardous settings.

Adolescent↗
PubMed1997

Silicone assisted, argon laser confinement of recurrent proliferative vitreoretinopathy related retinal detachment: a technique to allow silicone oil removal in problem eyes.

AIMS/BACKGROUND: Recurrent peripheral retinal detachments may occur in eyes treated with vitrectomy and silicone oil for retinal detachments complicated by proliferative vitreoretinopathy (PVR). The aim of this study was to assess whether laser photocoagulation could be used in the presence of silicone oil to confine and stabilise recurrent PVR related peripheral retinal detachments enabling the timely removal of the oil. METHODS: 10 patients with recurrent peripheral retinal detachments after vitrectomy and silicone oil insertion were treated with posturing and subsequent focal argon laser to circumscribe the area of recurrent detachment. RESULTS: This technique alone was sufficient to limit the area of retinal detachment in seven of the cases. The remaining three cases required relieving retinotomies because of increasing retinal detachment despite the laser. In all 10 cases the silicone oil was later removed without progression of the detached areas. CONCLUSION: Silicone assisted argon laser 'confinement' can be effective in stabilising eyes with peripheral retinal detachments allowing the subsequent removal of silicone oil.

Adult↗
PubMed1993

Experimental and predicted dual oximetry variability.

OBJECTIVE: We wished to determine whether the individual bias (mean difference) and precision (standard deviation of the difference) values of 2 variables, arterial oxygen saturation (SaO2) and mixed venous oxygen saturation (SvO2), could be used to predict the bias and precision values of the combined dual oximetry variable (SaO2-SvO2). METHODS: We simultaneously measured SaO2 by pulse oximetry and arterial blood gas co-oximetry and SvO2 by fiberoptic reflectance oximetry pulmonary artery catheter and venous blood gas co-oximetry in 238 data sets from 55 patients. Three different methods were used to predict the standard deviation of the difference of (SaO2-SvO2) [s delta(SaO2-SvO2)]: simple sum, root mean square (RMS) error, and RMS error with correction term. We derived the equation for the RMS error with correction term because initial results showed that the simple sum and RMS error methods did not predict s delta(SaO2-SvO2) well. The correction term accounts for the non-independence of simultaneous SaO2 and SvO2 measurements. RESULTS: The observed overall bias of the SaO2, SvO2, and (SaO2-SvO2) measurement methods were 0.17, -1.76, and 1.94, respectively. The observed overall s delta(SaO2-SvO2) of the (SaO2-SvO2) measurement method was 5.12. The simple sum method overestimated the actual s delta(SaO2-SvO2) by 38%, the RMS error method differed from the actual s delta(SaO2-SvO2) by 3%, and the RMS error with correction term method matched the actual s delta(SaO2-SvO2). CONCLUSION: The bias of a (SaO2-SvO2) measurement method is simply the bias of the SaO2 measurement method less the bias of the SvO2 measurement method. s delta(SaO2-SvO2) is best predicted by the derived equation, RMS error with correction term. The same principles and equations also apply to other situations in which 2 variables with the same dimensions are combined into 1 variable, such as (PaCO2-EtCO2) gradients and perfusion-pressure gradients. Although the difference between the s delta(SaO2-SvO2) predicted by the RMS error equation and the derived RMS error equation with correction term was small, the difference may be significant for other combined variables.

Oximetry↗
PubMed1991

Which tests are most useful in distinguishing between reactive thrombocytosis and the thrombocytosis of myeloproliferative disease?

In an attempt to distinguish between thrombocytosis in myeloproliferative disease (MPD) and reactive thrombocytosis (RT) the following aspects of platelet structure and function were evaluated: platelet size, platelet aggregation and adhesion, dense granule and alpha granule components. In addition plasma fibrinogen and von Willebrand factor antigen (vWFag) were measured. In all parameters measured there was a significant difference between normals and both categories of thrombocytosis, however there was considerable overlap between MPD and RT. Plasma fibrinogen emerged as the best single test to discriminate between MPD and RT, levels of less than 5.0 g/l indicating MPD and greater than 5.0 g/l indicating RT.

Antigens↗